Generally, in the case where a hinge pillar is retracted or inwardly deformed by an offset collision of a vehicle, an instrument panel member having an end linked to the hinge pillar is bent toward the vehicle body rear side around a portion near a center stay which is located substantially at a center part of the instrument panel member in the vehicle width direction.
If the instrument panel member is deformed as described above, a steering shaft supported on the instrument panel member is moved inward in the vehicle width direction, and a steering wheel is also moved inward in the vehicle width direction, as the steering shaft is moved. This means that the restraining position of a vehicle occupant by an airbag provided in the steering wheel is displaced inward in the vehicle width direction. It is necessary to design the structure of an instrument panel member itself, the fastening structure between an instrument panel member and peripheral members, and the layout of peripheral members relative to an instrument panel member in order to prevent such a drawback, while satisfying other requirements. Simply increasing the strength of an instrument panel member, however, may result in an increase in the weight of a vehicle body. Further, modifying the layout of peripheral members is not easy in view of the design constraints. Particularly, in recent years, there is a demand for taking measures against a pole collision or a small overlap collision of a vehicle. Thus, there is a need for a technology that enables to enhance safety of a vehicle occupant, while solving the above drawback.
Patent literature 1 and patent literature 2 are known as a technology for securely restraining a vehicle occupant by an airbag.
The conventional art disclosed in patent literature 1 is such that an accurate operation of an airbag device and the like is secured by preventing forward and upward turning of a steering wheel at the time of a vehicle frontal collision. Patent literature 1, however, is not designed to suppress movement of an instrument panel member and a steering wheel in the vehicle width direction, and fails to solve the above drawback.
The conventional art disclosed in patent literature 2 is provided with a turning device capable of changing the deployment direction of an airbag. According to this technology, at the time of a vehicle frontal collision, even if the head of a vehicle occupant is displaced in the left-right direction (in the vehicle width direction) with respect to the center of a steering wheel, the head of the vehicle occupant can be securely restrained by changing the deployment direction of the airbag in such a direction as to compensate for the displacement, with use of the turning device. In patent literature 2, however, a turning device for changing the deployment direction of an airbag is indispensable. Accordingly, the structure may be complicated.